1. Technical Field
The present invention relates generally to an improved circuit system and in particular to a resistor. Still more particularly, the present invention relates to a precision voltage controlled diffusion resistor.
2. Description of the Related Art
A resistor is an electrical device that may convert energy into heat. The letter R is used to denote the resistance value of a resistor. With this device, two possible reference choices are present for the current and voltage at the terminals of the resistor. One is current in the direction of the voltage drop across the resistor and another is the current in the direction of voltage rise across the resistor.
Some existing problems with respect to resistors include transmission line impedance mismatching (caused by line width variations through etching), the physical size required for diffusion resistors, and process variation in diffusion resistors. Currently, existing solutions for these problems include special Microwave Integrated Circuit (MIC) processes to make trimmed resistors. This type of process involves using a laser to trim the resistors. The resistance is measured and a laser is used to reduce the size of the resistor. This type of process requires much time and is expensive to perform on a per circuit basis. Alternatively, high-precision discrete components are soldered or bonded to an integrated circuit (IC) or package. These currently used solutions are expensive with respect to the manufacturing of semiconductors. Further, these existing solutions are difficult to integrate into a silicon IC process because of the size of components and/or specialized manufacturing requirements needed to trim the devices. Further, discrete or trimmed components are not adjustable after the manufacture of a product.
Therefore, it would be advantageous to have an improved diffusion resistor that overcomes the problems of the existing solutions.